Carburetor



y 17, 1932- v a. M. BICKNELL 5 CARBURETOR Fild June 28, 1930 s Sheets-Sheet 1 INVENTOR GEORGE M. BIC KNELL a ATTORNEY s. M. BICKNEL L CARBURETOR May 11,1932.

Filed June 28. 1930 .5 Sheets-Sheet 3 INVENTOR GEORGE M. BIGKNELlL V Feterited May 17, 193 2 Tao STATES ram o cla on m. Brennan, or s'r. LOUIS, mrssounr, ASSIGNOR r canons. cannumaron. J I 'IIOH, or s1. LOUIS, mrssounr, A coarona'rron or DELAWARE cmeunmon It will be understood that the invention is susceptible of many modifications, and, accordingly, .I do not wish to be'limited in my protection, except as set forth in the accompanying claims.

This invention relates to carburetors, and particularly to carburetors of the type in which the spray of fuel and air is discharged from the nozzle in a downward direction. 1

It is an object of the invention to produce a carburetor of this general type in which the air passages may be made as large and unrestricted as possible in order to permit the motor to draw in the fullest possible charges, and thereby attain the. maximum volumetric eficiencypit is a further object of this invention to produce a suction operated spray carburetor having one or'more suction operated nozzles for supplying the full requirernents of fuel to the carburetor during constant speed operation, and an'accelerating device for supplying additional fuel for acceleration purposes, said accelerating device bein entirely independent of the suction whic may exist in said carburetor.

lt is a further object of this invention to provide a suction operatedspraycarburetor of down draft type, having suction o erated fuel supply devices for constant spec opera tion, and an accelerating device for acceleration only, with means for directing the fuel from said accelerating device to a point of maximum suction in said carburetor, without permitting the fuel to come in contact with the outer wall of the mixing conduit and to thereby avoid the diliiculties in distribution which might arise during low speed operation if the fuel from "the accelerating pump should be permitted to come in contact with and trickle down one side of-the mixin conduit. F a

%t is a further object of this invention to produce agenerally new and improved structure of the above described character.

The invention will be better understood upon reference to the following description and claims and the accompanying drawings, referring to which:

Figure 1 shows a diagrammatic vertical sectional view of the carburetor taken along Application filed ulieta, 1930. Serial N'o. 464,451.

the broken line 11 of Figure 3 and looking in the direction of the arrows, certain parts being broken away for better illustration of others."

Figure 2 shows a vertical sectional view of the carburetor taken along the line 2-.-2 of" Figure 3 looking in. the direction of the arrows, the choke being shown in closed position. a 1

Figure 3 shows a plan view of the carburetor.

. Figure 4 shows a sectional plan view of parts of the carburetor taken along the line 4-4 of Figure 2. Figure 5 is a detailed view showing the upwardly conducting idle tube.

Figure 6 is a detailed view showing the downwardly conducting idle tube.

Figure 7 shows a sectional View of thepump discharge jet and associated parts taken along a i the line 33 of Figure 3 looking in the direction of the arrows.

Figure 8 is a detail sectional view of the thimble 23. 1 I

The carburetor comprises a main body member 1, having avertically extending air chamber 2 at the upper end thereof. This passageway is contracted into a vventuri, the throat of which is indicated at 3, and the venturi tapers gradually downwardly and an outwardly as indicated at 4, terminating in the cylindrical outlet passageway 5. This outlet is surrounded by a flange 6 which is provided with bolt holes 7 or any suitable means by which it may be attached .tothe manifold on an internal combustion engine:

A butterfly throttle 8 mounted in conventional manner upon a shaft 9 is provided, and an-operating arm 10 is attached to the shaft 9 fon operation by any suitable means. The upper part of the body of the carburetor is expanded to a size sufiicient to receive the fuel bowl 11 which is attached to a support member 12. The upper rim of the bowlis held in fluid tight relation to the support member at'13, a suitable gasket bein pro vided as shown. The support member is car v ried on the upper end of the body of the carburetor and retained in position by-bolts 14, as shown in Figure 3, or other suitable renmeans. The support member is provided with an extension 15 extending downwardly into the bowl 11 and this extension is threaded at '16 to receive the end of a flanged nozzle member or inverted stand-pipe 17 which when screwed into the threads 16 retains the fuel bowl tightly in place. The standpipe is provided with a restricted portion or primary venturi 18 which tapers gradually out to the cylindrical bore 19 of the standpipe.

The extension 15 of the support member is provided with a well or downwardly extending opening 20 which is in -communication with the atmosphere at its upper end. In the lowerportion of this well a concentric member 21 is fitted and this member carries an accelerating well 22 and an inverted thin!- ble 23 havin one or more accelerating holes 24.- formed t erein. The member 21 15 provided with a bore 25 to loosely receive a nozzle member 26. This nozzle member extends upwardly to a point just above the float level in the bowl and below the top of the thimble as shown, and it extends downwardly to a,

point near the throat of the venturi 18. It will be understood that the nozzle member is attached to the support member 12 by threads 27 or other suitable means.

A spider or cross member 28 is formed in the member 12 to extend across the lower part of the well 20 to receive the threads 25 andv 27. A bore 29 is formed extending transversely into the extension 15 and longitudiother suitable means.

nally through the spider 28. This bore-is threaded as shown to receive a jet nozzle 30 "which-controls the main fuel entrance to the carburetor. It will be understood that the bore 29 communicates'with the bore 25 and through the accelerating holes 24 with the well 22.

Fuelis supplied to the fuel bowl 11 from a conventional fuel pump, (not shown) or A pipe connection 31 receives the fuel and delivers it to a passage 32 in the support member. A vertical bore 33'is formed in the support memberand communicates with the interior of the fuel bowl and with the bore 32. .A valve seat member 34 is threaded into the bore- 33, and a needle valve 35 is mounted to seat in the member 34 to control the admission of fuel to the carburetor. A conventional float 36, pivotedat 37 operates the valve, thereby maintaining a fuel level in the carburetor substantially at the line A- A, as shown in Figure 1.

The support member 12 is provided with a vertical bore to receive the idling tube 38 as shown. This bore intersects the bore 29 to receive fuel therefrom. The tube 38 is pro vided with a restricted portion 39 in which is formed a small meteringport 40 which initially controls the richness of the idling mixture. The second port 41 is formed in the upper end of the tube ,38 to discharge into the chamber 42 at the upper end of the tube. 1A

plug 43 is soldered to the upper end of the tube 38 and closes the upper end of the chamber. v

A transverse bore 45 communicates with the chamber 42 and also with a second chamdischar e outlet 51 and mixing chamber 52 of the car uretor.

A pump cylinder 53 is attached by suitable means such as cap screws 54 to the support member 12. An inlet and discharge passage 55 leads from the lower end of the pump cylinder to a oint near the upperend of the transverse passage 56 in the support member. The passage 56 communicates with a discharge outlet57 through a check valve 58 and with a spray nozzle 59 as shown in Figure 7. The inlet conduit for the pump is a tube 60 threaded into the body member 12 as shown and extending below the level of the fuel in the bowl 11. An inlet check valve 61 is mountcylinder w ere it communicates with the ed in the'tube to be held closed by its own weight except when ope ed by the suction of the pump. The upper end of the'inlet conduit 60 communicates with a vertical bore 57 and a cross hole 62 serves to convey fuel from the bore 57 to the bore 56. v

The pump is provided with a piston 63 which is connected by a link '64 and connect-' ing rod 65 to the operating arm' 10 of the throttle. A choke member 66 of frusto-conical formation is mounted on the stand-pipe 19.

The choke member is provided with an annulari-rece'ss67 which is engaged by the arms of the yoke 68 mounted on a rock shaft 69. Suitable connections are made for manually operating the rock shaft'so that the choke may be moved into the space between the venturi and the standpipe as shown 1n Figure 2 for starting purposes, and returned to the position shown in Figure 1 for normal operating conditions. The operation of the device is as follows:

Fuel being supplied-to the carburetorthrou h the connection 31 it ismaintained at sus tantially the level'AA by the float mechanism in a conventional manner. I This fuel passes through the metering jet 30 into the bore 29 and up around the nozzle 26 in the bore 25 to the same level as in the bowl.

fuel also flows out through the accelerating holes 24 in the thimbleand fills up the well 4 22 to the same level. Fuel also flows into the idling tube 38 through the port 40.

thus cuttingoff the flow of air through theannular passa e between the end of the stand plpe and the t roat of the venturi. The suction of the engineas it is operated by the starting means draws the air through the stand-pipe and the primary venturi 18 which, being restricted by the end of the nozzle 26; produces a high velocity in the air stream at that point. The suction communicates through the nozzle with the well 22 and fuel is drawn up to the top of the nozzle through the space between the thimble 23 and the upper end to the nozzle. As soon as the 'engine starts to operate under its own power its speed will increase and the increased suction will lower the level of fuel in the well 22 so that air will be drawn in through the accelerating holes 24 preparing the fuel in the form of an emulsion for breaking up into a spray at the throat of the primary venturi.

The increased suction will also cause fuel to be drawn up through the tube 38 and the connecting passages to the port 50 where it will be discharged along with air, which is bled in at the port 44. When the engine is sufficiently warmed up the choke 66 is wholly or partially withdrawn to the position shown in Figure l and a comparatively large quan-.

tity of air passes down through the space between the bowl of the carburetor and the enlarged portion of the body member 1 so that the mixture is further diluted inthe mixing chamber 52. It will be understood that the suction continues to draw fuel from the nozzle as heretofore describedflbut less rapidly when the choke is withdrawn than otherwise. I

When the throttle is substantially closed and the choke 66 is in the position shown in Figure 1 there will be substantially no suction in the mixing chamber 52 to draw fuel from the nozzle and under these conditions the requirements of the motor will be met by fuel which is drawn in through the port from the idling tubes. It will be understood that the position of the edge of the throttle valve 8 with respect to the port 50 will control the amount of suction applied at that port and that when the throttle valve is slightly opened the area of this port which is exposed to the suction, becomes greater,

' thus tending to draw in more fuel as the motor requires it.

The throttle is so connected to the accelerating pump that upon a closing movement of the throttle the pump piston will be with-- down into the primary inlet to prevent the tendency to undue leanness when the motor is suddenly accelerated.

It will be noted that the nozzle 59 is mounted to discharge into a substantially unrestricted portion of the primary air inlet which is anterior to the primary and main venturis, so that suction developed during high speed operation of the carburetor will not cause a continuous discharge offuel 'therethrough. 1t will also be noted that when the velocity of air flowing through the carburetor is not sufiicient to instantly break up and vaporize the stream of fuel discharged from the nozzle 59, this stream. will come in contact with and trickle down the walls of the primary mixing conduit/to the lower end bf the member 19, where it will be dripped off at, the throat of the venturi 3, at which point the velocity of air is comparatively high. 'In this manner I can obtain a constructionin which the accelerating pump will not be caused to discharge fuel at constant high speed operation of the" carburetor and yet the fuel from the pump will be conveyed into the middle of the air stream at the main venturi so that the maximum vaporization will be obtained.

I claim 1. In a carburetor, a body member having an annular seat, an extension of said body member substantially coaxial with said seat; a down draft passageway in said extension; a

standpipe threaded into the lower end of said extension and having aflange thereon, and a fuel bowl having its upper rim held in con tact with said seat by screwing said standpipe in place.

2. In a'carburetor a downwardly discharging fuel nozzle; a thimble fitted over the end of said nozzle and forming an annular passageway between said thimble and said nozzle; means for maintaining a fuel level in said thimble at a point near the upper end of said nozzle, a well surrounding said'thimble and a port in the wall of said thimble at least a' portion of said port being above said fuel level. 1 F

3. In a carburetor, a downwardly discharg- -ing fuel nozzle; a thimble fitted over the end of said nozzle and forming an annular passageway between said thimble and said nozzle; means for maintaining a fuel level in said thimble at a point near the upper end of said nozzle, a well surrounding said thimble and a plurality of vertically spaced ports in the wall of said thimble. w v

4. In a carburetor, a downwardly conducting passageway; a concentric fuel nozzle in said passageway; a well surrounding the upper end of said nozzle; means for supplying fuel to said well, and an inverted thimble loosely surrounding the upperv end of said nozzle, said thimble having one or more air bleed holes therein, and means forming a well surrounding said thimble.

5. 'In a carburetor, a downwardl conducting passageway; a concentric fue nozzle in said passageway; a well surrounding the up- .per end of said nozzle; means for supplying fuel to said well, an inverted thimble loosely surrounding the upper end of said nozzle,

, and a plurality of ports at different levelsin at a point near the throat of said main venturi, means comprising a nozzle for supplying fuel to said primar venturi at a point near the 'throat thereo means forming a source of fuel supply, a well connected to re- .ceivefuel from said source of supply and to supply fuel to said nozzle,and an air supply conduit for said well, said air supply conduit, having an upwardly directed air receiving opening exposed to the impact of air flowing through said'mixing conduit.

7. In a carburetor, means forming a mixing conduit, a downwardly directed main venturi in said conduit, a throttle valve below said venturi, a primary venturi mounted above saidmain venturi, said primary venturi discharging at a point near the throat of said main venturi, means forming a main fuel discharge outlet arranged to discharge at a point near the throat of said rimary venturi, means forming a source of uel supply, means forming a low speed fuel discharge outlet adjacent said throttle, a well connected to supply fuel to said main fuel discharge outlet, branched conduit means having an inlet to receive fuel from said source of supply and conn'ectedto both of said discharge outlets, and an air supply conduit for said well, said airsupplyconduit having an opening within'said mixing conduit.

8. In a carburetor, means forming a sub-' stantially vertical mixing conduit, a throttle valve at the lower end of said conduit, 0.

downwardly directed main venturi in said conduit above said throttle valve, means forming a source of fuel supply, a pump connected to receive fuel from said source, said pump having a member connected to and operated by said throttle for discharging a 'quantity of fuel into said mixing conduit when said throttle is opened, said pump having a discharge nozzle arranged to discharge at an angle to the axis of said mixing conduit, and a substantially vertical member mounted in the line of discharge of said pump nozzle, whereby the stream of fuel fromsaid nozzle may be prevented from striking the outer.

wall of said mixing conduit.

9. In a carburetor, means forming a sub"- charging into saidinixing conduit st'antially vertical down draft mixing conduit,'said conduit having main venturi between the ends thereof and a primary mixing conduit substantially coaxial with said main venturi and discharging at a point near the throat thereof, a main fuel supply device for supplying fuel to said primary mixing conduit, an auxiliary fuel supply device having a nozzle for discharging a stream of fuel,

said nozzle being mounted at an angle to the vertical and being directed to discharge againsta wall of said primary mixing conduit, whereby under conditions such that the air velocity in said carburetor is so low as to be incapable of instantly breaking up and vaporizing said stream, the unvaporized fuel atively restricted and unrestricted portions,

said mixing conduit comprising inner and outer passages, means for admitting air to the upper end of saidpassages, and a mixture discharge outlet at the lower end, said inner passage having an air bled main nozzle, a

throttle valve at the lower end of said mixing conduit, a low speed fuel discharge port adjacent said throttle valve, saidlow speed port and said main nozzle being interconnected, an auxiliary fuel supply device comprising a nozzle discharging into one branch of said mixing conduit at an angle to the vertical, the stream of fuel from said auxiliary fuel supply device discharging against a wall of said inner passageway when the air velocity is so low as not to substantially deflect it, the lower end of said inner passageway terminating at a point of high. restriction in said outer passage.

11. In a down draft carburetor, means forming. a substantially vertical mixing conduit, a throttle valve at the lower end of said conduit, said conduit comprising an outer passage and a substantially concentric inner passage, said passages converging at the lowerend'of the inner passage, a main venturi in said conduit havinga throat substantially at the level of the lower and of the inner passage. said inner passage comprising an annular wall terminating at'its lower end substantially at the level of the throat-of'said venturi, a low speed fuel supply nozzle disat a point adjacent said throttle, a fuel pump having a nozzle mounted atan angle to the vertical and directed towards a wall of said inner passage, said pump being connected to and operated by said throttle and adapted to discharge a stream of fuel towardsaid wall of said inner conduit when the throttle is opened, whereby when the air velocity in so I Q let, a throttle for controllingsaid discharge saidcarburetor is -toolow to instantly break up the fuel stream issuing from the mag, said stream will impinge against and rected by the wall of said inner passageway 5 to the throat of said main venturi.

12. In a carburetor, means forming a mixing conduit, said mixing conduit having an unrestricted air inlet of constant size regard 1 less of suction and a mixture discharge outoutlet, a venturi anterior' to said throttle, y said 'venturi having a throat forming the point of high restrictionand high suction in said mixing conduit, suction o erated means for discharging'a mixture of uel and air to the throat of said venturi during normal and 7 high speed operation, suction operated means for discharging a mixture of fuel and a air to said mixing conduit adjacent said throttle for'low speed operation, an accelerat ing pump for discharging additional fuel to said mixing conduit for acceleration only, said pump comprising a piston, a cylinder, inlet and outlet check valves and a discharge nozzle, said discharge no'zgle having its out- .let at 'a point of low/restriction and low 'suction in said conduit, whereby the tendency of said pump to continuously discharge fuel. 5 during hi 'hspeed operation of .the carburetor W111 minimized.

13. In a down draft carburetor, means forming a substantially vertical mixing conduit, said mixing conduit com rismg. a downwardly directed; air inlet, 7' Inner and outer passages and a mixing chamber at thelower end of said mixing conduit, a main 'venturi at-the upper end of said mixing chamber, said inner conduit extending tothe throatof said main venturi, the walls 'of 4 said inner conduit and-the throat of said venturi forming a restriction in said outerconduit, said inner conduit having a restricted" portiontherein, a suction operated nozzledischarging at said restricted portion, an

[ 65 accelerating pump and. a discharge nozzle' forsaidaccelerating pump having itsoutlet in one of said passages at a point below the levelof said air inlet and: above the level of y the restricted portion in the branch which I it discharges;

In testimony whereof fl afix my signature F day oi rirmaa RGE M. mommy; 

